606.3 Duct and Plenum Insulation, Sealing and Testing

Supply and return air ducts and plenums, air handlers and filter boxes shall be insulated and sealed in accordance with Section C403.2.7.1.1 of the International Energy Conservation Code. The exception in Section C403.2.7.1.1 shall not apply.

Ductwork that is designed to operate at static pressures greater than 3 inches water column (747 Pa) and all ductwork located outdoors shall be leak-tested in accordance with the SMACNA HVAC Air Duct Leakage Test Manual. Representative sections totaling not less than 25 percent of the total installed duct area for the designated pressure class shall be tested. Positive pressure testing is acceptable for negative pressure ductwork. Duct systems with pressure ratings in excess of 3 inches water column (747 Pa) shall be identified on the construction documents. Duct leakage shall not exceed the rate determined in accordance with Equation 6-3.

F = CLP0.65

(Equation 6-3)

F	=	maximum leakage in cfm/100 ft2 duct surface area;
CL	=	4, duct leakage class, cfm/100 ft2 at 1 inch water column.
P	=	test pressure, which shall be equal to the design duct pressure class rating inches of water column.